Method of electromagnetically regulating the output of compressors



Oct. 4, 1938. HOERBlGER r AL 2,132,070

METHOD OF ELECTROMAGNETICALLY REGULATING THE OUTPUT OF COMPRESSORS Filed Aug. 22, 1936 Ill/III 1111 Patented ca 4, 1938 2,132,070

nin'rnon or mc'raomoxnncmy anogggmo rm: on'rru'r or columns- Alfred Heel-hirer, Maner, near Vienna, and Friedrieh Sohabeteberger, Vienna, Austria Application August 22. 1936, Serial No. 97,456

In Germany February 24, 1936 1 2 (flalml. (Cl. 137-139) This invention relates to a method of and hand for the remainder of the pressure stroke means for the electromagnetic regulation of the the force exerted by the excited magnet upon the output of compressors. closed suction valve is not capable of overcoming Our U. S. Patent No. 2,035,963 discloses an the rapidly increasing pressure in the cylinder, automatic load regulator for a piston compressor, which takes effect against the opposite side of the 5 in which, by the pole reversal of the electromagvalve. In this connection it is even possible, nets by means of magnet coils of different polarduring a complete revolution of the compressor, ity disposed in a row, the troublesome residual to effect two pole reversals displaced 180 relamagnetism of the electromagnets is eliminated. tively to each other, of which one always falls At the same time the play of the magnets is acwithin the suction stroke and thus produces no 10 curately attuned to the individual phases of result with regard to the regulation of this end movement of the suction valve. The play of the of the cylinder. If however the valve controlsuction valve of a compressor the regulating of ling magnets t o t and at the ear ends which is effected by keeping the suction valve be connected together, then the ineflective one open for a greater or less part of the pressure of these pole reversals (which occurs within the 15 stroke, is as follows: The suction valve is open suction stroke) at one end of the cylinder brings throughout the entire suction stroke, also open about closin of the Suction va ve at the o her during a portion of the pressure stroke correend of the cylinder, since the suction and pressponding to the desired reduction of output, and Sure Periods n frcht of and behind the P o :0 closed during the remainder of the pressure or are Offset relatively to each Otherdelivery stroke. In the method forming the sub- TWO forms of ce s cti em odying the inject matter of the above-mentioned patent there vention are shown, by way of example, in the is provided, in accordance with this valve play, accompanying drawing. in w c alternate activation and. neutralization of the K- 1 Shows diagrammatically ah -8 electromagnets, with reversal of polarity after ment Of connections in which only one valve 25 each neutralization. This arrangement necessicchilr'clling magnet 15 providedtates a complicated system of connections. l- 2 s a Se d diagram for a arrangement The present invention provides a method of embodying tWO co selectromagnetic regulation of the output of com- The rotating s Which s driven for expressors in which the troublesome residual magmp at half the sp d of t mpr ss s 30 netjsm f the magnets is nk mm g d, provided with two semi-annular contacts l2 and According to the invention use is made of the which are displaced relatively o e difference in magnitude between the attracting Other, end One Which, by means of Suitably D and retaining forces of the open and closed magsitioned sliding contacts II and i5 is at all times u circuit, respectively on t one hand, connected to the positive pole and the other of 35 and the pressure forces -m upon t open which by sliding contacts l6 and i1 is at all and closed suction valve, respectively on t times connected to the negative pole of a source other hand, The force of t magnet 1 arof current 29. Upon a distributing bar or bridge ranged to be such that it is indeed capable of which is normally fixed in P s t t e e 40 holding the lifted valve open against the action P v two Pairs of relatively displaced c 40 of the forces tending to close it at the commence- -ets 9, 20 a d 12 the spaci of which s ment of the pressure stroke, that is to say against equal to the radial displacement of the two semithe force of the valve springs and of the delivery annular contacts from each other. Each two pressure. When once the suction valve is closed, adjacent contacts l9, III and II, 22, respectively,

however, so that the rapidly increasing pressure pertaining to the rotary contact bridge ll, and in the cylinder of the compressor bears upon associated with diiferent contact rings l2, II, it, even the excited magnet is not capable of are connected together and each pair is conlifting it from its seating. The invention thus nected to one end of the magnet coil 23. At each consists in an arrangement by which, in a prerevolution of the contact disc II the direction ferred embodiment, during the pressure stroke, of the current flowing through the coil thus 50 at the moment of the intended closing of the changes twice. This meansprovided the consuction valve, a pole reversal of the magnet govtact disc I I rotates at half the speed of the comerning the suction valve is efl'ected, which en- Dresser-a single pole reversal-of the magnet 23 ables the valve to close in response to the action during one revolution of the compressor. By

56 of its normal closing forces, whereas on the other adjustment of the contact bridge II in its orientation about the axis of the disc II which can be eflected by hand as shown at 49, ll, or by any automatic means for imparting an impulse, this alteration in the direction 01' flow of the current, which corresponds each time to a pole reversal or the magnet, is caused to take place at the desired point in the pressure stroke of the piston.

The cylinder 30 has the piston 3i, and also has a suction valve 32 held normally closed by a spring 33 acting on lug 31 carried by valve stem 35 and also acting against abutment 33. Electromagnet 23 has pivotally mounted armature 34 pivotally connected to valve stem 35. Crank disc 36 drives piston 3| and also by shaft 38 drives rotating disc II. The distributing bar or bridge I8 is freely journalled on shaft 39 and can be adjusted into any desired position by adjusting means 40, ll.

The rotating disc I I may however also be driven at the same speed as the compressor. In this case two pole reversals of the magnet 23 take place at each complete revolution of the compressor, these pole reversals being displaced relatively to each other. Thus if the one falls within the pressure stroke the other necessarily falls within the suction stroke. Since during this latter phase the valve is held open in any case by the force of the flowing medium this second pole reversal has no efi'ect whatever upon the valve play. This form of construction has incidentally the advantage that the magnets for the controlling of the suction valves in front of and behind the piston can be connected together. Since the suction and pressure periods on both sides of the piston are displaced 180 relatively to each other each pole reversal which takes place without efiect upon the one suction valve brings about a closing of the suction valve on the other side of the cylinder. With the arrangement of connections shown in Fig. 1 only one magnet coil 23 is required. But there are four points of interruption.

The same result as regards the controlling efiect can be obtained with the form of construction outlined in Fig. 2, in which two coils 24 and 25 are provided for each valve. The connection 26 between these two coils is connected for example, through ground or conducting mass, to the one pole of the current source, while the two other ends 21 and 28 are alternately brought into connection with the second pole of the current source by means or the contact disc ii in conjunction with the adjustable contact bridge I8. With this arrangement there are thus two or more pairs oi coils 24, 25, but only two points of interruption.

We claim:

1. In the operation of an electromagnetically controlled valve actuating mechanism for a fluid piston compressor having a suction valve normally closed by a resilient force and further having an electromagnet with a single actuating winding adapted when energized to apply to said valve 9. pushing force tending to open the same, the method of electromagnetically regulating the compressor load which consists in applying to the magnetic'circuitoi said electromagnet at the beginning oi the compression stroke oi said piston a magnetomotive force in one direction of magnitude suflicient to produce an opposing attractive force greater than said normally closing resilient force and then maintain said valve open, reversing said magnetomotive force at an instant intermediate oi the compression stroke of said piston, and maintaining the pushing force exerted by said electromagnet on said valve at all times less than the fluid pressure exerted against said valve at the end of its compression stroke with said valve closed.

2. In the operation of an electromagnetically controlled valve actuating mechanism for a fluid piston compressor having a suction valve normally closed by a resilient force and further having an electromagnet with a single actuating winding adapted when energized to apply to said valve a pushing force tending to open the same, the method of electromagnetically regulating the compressor load which consists in causing said electromagnet at the beginning of the compression stroke of said piston to produce an opposing attractive force greater than said normally closing resilient force and thereby maintain said valve open, then at an instant intermediate of the compression stroke of said piston reducing to zero and reversing in direction the magnetomotive force applied to the magnetic circuit of said electromagnet and thereby reducing to zero the opposing attractive force produced by said electromagnet and thereby closing said valve, and then at a subsequent instant intermediate of said compression stroke and continuing to the end of the compression stroke causing said electromagnet to produce an opposing attractive force less than the resilient and pressure forces then tending to keep said valve closed but suflicient to overcome said resilient iorce alone.

ALFRED HOERBIGER. FRIEDRICH SCHABETSBERGER. 

